Modular synthesis of graphene nanoribbons and graphene substructures from oligo-alkynes

ABSTRACT

A method for the synthesis of carbon-based structures, particularly graphene substructures and ribbons, from oligo- and poly-alkyne starting materials.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 13/658,886, filed Oct. 24, 2012, the disclosure of which isincorporated herein as if set forth in its entirety. U.S. applicationSer. No. 13/658,886 claims priority from U.S. Provisional ApplicationSer. No. 61/554,031, filed on Nov. 1, 2011, the disclosure of which isincorporated herein as if set forth in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH & DEVELOPMENT

This invention was made with government support under Grant No.CHE-084686 awarded by the National Science Foundation. The governmenthas certain rights in this invention.

FIELD OF THE INVENTION

The field of the invention generally relates to the synthesis ofconjugated, cyclized carbon-based structures from oligo-alkyne startingmaterials, and more specifically to the synthesis of carbon-richconjugated polyaromatic nanostructures from oligo-alkyne startingmaterials via cascade radical cyclizations.

BACKGROUND OF THE INVENTION

The 2010 Nobel Prize illustrates the evolution of graphene from a merecuriosity to the new face of carbon. Graphene is a flat sheet of sp²carbon atoms arranged into hexagons, giving it the appearance of ahoneycomb lattice. See Geim, A. K.; Novoselov, K. S. The Rise ofGraphene, Nature Materials. 2007, 6, 183-191, which may be accessed at:http://www.nature.com/nmat/journal/v6/n3/abs/nmat1849.html.

Graphite ribbons are predicted to have very interesting electronicproperties which combine the relatively small band gap with highswitching speeds and carrier mobility. See (A) Li, X.; Wang, X.; Li, Z.;Lee, S. Dai, H. Science 2008, 319, 1229; (B) Wu, J.; Pisula, W.; Müllen,K. Graphenes as Potential Material for Electronics, Chem. Rev. 2007,107, 718-747, which may be accessed athttp://pubs.acs.org/doi/abs/10.1021/cr068010r; and (C) Allen, M. J.;Tung, V. C.; Kaner, R. B. Honeycomb Carbon: A Review of Graphene, Chem.Rev. 2010. 110, 132-145, which may be accessed athttp://pubs.acs.org/doi/abs/10.1021/cr900070d.

In order to take the full advantage of graphene as a building block inthe new generation of materials, one needs to prepare it in a chemicallyhomogeneous and well-defined state. Subtle variations in structure(zigzag vs. chair arrangement at the edges, size and shape) are known toaffect the electronic properties very strongly. This challenge has to bemet through the rationally designed chemical approaches to the synthesisof graphene in order to advance the future development of the field ofcarbon-based nanoelectronics. Not surprisingly, a number of syntheticapproaches to such ribbons illustrated on the left have been developed.See Goldfinger, M. B.; Swager, T. M. J. Am. Chem. Soc. 1994, 116, 7895.Scherf, U. J. Mater. Chem. 1999, 9, 1853; and Berresheim, A. J.;Mueller, M.; Muellen, K. Chem. Rev. 1999, 99, 1747. Mallory, F. B.;Butler, K. E.; Berube, A.; Luzik, E. D.; Mallory, C. W.; Brondyke, E.J.; Hiremath, R.; Ngo, P.; Carroll, P. J. Tetrahedron 2001, 57, 3715.Several of these prior art syntheses are shown in FIG. 1.

There are both practical and conceptual limitations to the currentapproaches to the preparation of graphene ribbons. While the currentsyntheses often provide an elegant solution to the design of a symmetricfunctionalized graphene pieces, efficient and flexible approaches tonon-symmetrically carved and/or substituted graphene substructures are,at best, scarce. See Kuninobu, Y.; Seiki, T.; Kanamaru, S.; Nishina, Y.;Takai, K. Synthesis of functionalized Pentacenes from IsobenzofuransDerived from C—H Bond Activation, Org. Lett., 2010, 12, 5287-5289, whichmay be accessed at: http://pubs.acs.org/doi/abs/10.1021/ol102349r.

BRIEF DESCRIPTION OF THE INVENTION

Briefly, therefore, the present invention is directed to a compoundcomprising repeat units having the structure (I):

In the compound of structure (I), n is an integer having a value of atleast three; R_(A1), R_(A2), R_(A3), and R_(A4) are each independentlycarbon or nitrogen; R₁, R₂, R₃, and R₄ are each independently hydrogen;an election pair; a substituted or unsubstituted aliphatic moiety; asubstituted or unsubstituted aromatic moiety; a substituted orunsubstituted alkoxy moiety; cyano; nitro; sulfinate; sulfonate; amino;or a substituted or unsubstituted alkylamino; or any two of R₁, R₂, R₃,and R₄ together with the atoms to which they are bonded may form a fusedcycloalkyl, a fused heterocycloalkyl, a fused aromatic ring, or a fusedheteroaromatic ring; T₁ and T₂ are each independently selected from thegroup consisting of hydrogen, an aliphatic moiety having from about 1 toabout 18 carbon atoms; an aromatic moiety having from three to 18 carbonatoms; an alkoxy moiety having from 1 to about 6 carbon atoms; and acyano moiety.

In the compound of structure (I), at least one of the repeat unitscomprises an R₁ moiety having the structure (II):

In the context of structure (II), Y comprises a reactive moiety selectedfrom the group consisting of bromine, iodine, xanthate, or a carbonylcompound which can be converted into a radical; and Z comprises a groupselected from the group consisting of O, S, S(O), SO₂, CR₇R₈, or NR₉;and R₇, R₈, and R₉ are each independently selected from the groupconsisting of hydrogen, an aliphatic moiety having from 1 to about 10carbon atoms; an aromatic moiety having from three to 10 carbon atoms;and an aromatic moiety having from 14 to 20 carbon atoms.

The present invention is further directed to polyaromatic compoundsprepared by cyclizing compounds having structure (I).

The present invention is still further directed to a method of cyclizingcompounds having structure (I).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a depiction of prior art syntheses of graphene.

FIG. 2 is a depiction of syntheses of graphene ribbons and substructuresaccording to the present invention.

FIG. 3 depicts Scheme 1, which is a sequence of reactions for preparingbis-alkyne model compounds having a moiety representing the “weak link”starting from 3-iodophenol.

FIG. 4 depicts a sequence of reactions for the modular assembly ofbis-alkyne model compounds of the type prepared according to thesequence depicted in FIG. 3 with additional aromatic building blocks tothereby prepare an ortho-poly-alkyne compound having multipleortho-alkyne moieties.

FIG. 5 depicts the Scheme 2 sequence of cascade cyclization ofsubstituted enediynes and PES for the transformation of enediyne 2b(B3LYP/6-31+ (d,p), kcal/mol).

FIG. 6 depicts Scheme 3, which is a sequence of selective radicalinitiation through the use of xanthate as the weak link in atetra-alkyne reactant.

FIG. 7 depicts Scheme 4, which is a sequence of reactions for thesynthesis of o-aryleneethynylene tetramer, the mechanism of cascadecyclization, and the highest occupied molecular orbital (HOMO) of theproduct.

FIG. 8 depicts synthesis of oligo-alkynes with an even number of alkynemoieties using a “linchpin” with two alkynes

FIG. 9 depicts synthesis of oligo-alkynes with an odd number of alkynemoieties using a monoalkyne “linchpin” (or any other core molecule withan odd number of alkynes).

FIGS. 10 and 11 depict the modular approach to the synthesis of widergraphene ribbons when naphthalenes or anthracenes are used instead ofpreexisting benzene rings in the reactants.

FIGS. 12A through 12E depict Scheme 5, which provides a sequence ofreactions for preparing highly cyclized structures with both cyano andalkoxy (methoxy and 1,3-dioxolane) functionality.

FIG. 13 depicts oligo-alkyne compounds based on heteroaromatic buildingblocks

FIGS. 14A through 14D depict the synthetic scheme for the preparation ofoligo-alkyne of compound A of FIG. 13.

FIGS. 15A through 15C depict the synthetic scheme for the preparation ofoligo-alkyne of compound B of FIG. 13.

FIGS. 16A through 16C depict the synthetic scheme for the preparation ofoligo-alkyne of compound C of FIG. 13.

DETAILED DESCRIPTION OF THE EMBODIMENT(S) OF THE INVENTION

The present invention is directed to the synthesis of conjugated,cyclized carbon-based structures from oligo-alkyne and poly-alkynestarting materials, and more specifically to the synthesis ofcarbon-rich conjugated polyaromatic nanostructures from oligo-alkynestarting materials via cascade radical cyclizations. In particular, thepresent invention is directed to a method of preparing substructures ofthe graphite allotrope. Even more particularly, the method of thepresent invention is directed to the design of a new organic syntheticroute which may open access to a variety of graphene substructures.According to the method of the present invention, ortho oligo-alkyne andortho poly-alkyne chains of varying sizes, equipped with differentfunctionalities, are built in a modular fashion using well-characterizedand reliable Sonogashira coupling chemistry. In the key step, thesesystems are then “zipped” up via a cascade of fast and selective radicalcyclizations. See FIG. 2, which depicts a model synthesis of grapheneribbons and substructures according to the method of the presentinvention.

In general, the ortho oligo- or poly-alkyne chain as depicted in themodel synthesis depicted in FIG. 2 may comprise multiple aromaticmoieties, each of which may be the same or different.

In some embodiments, an ortho oligo- or poly-alkyne compound for use inthe method of the present invention has the following Structure (I)comprising the general aromatic-alkyne repeat unit:

In the above structure (I), n is an integer having a value of at leastthree, preferably at least four. The value of n may be between 3 and 25,such as between three and fifteen, such as between about three and about10, such as between about three and six. In some embodiments, the valueof n is at least 4, such as between 4 and about 25, or between four andfifteen, or between four and 10, or even between four and seven. Thevalue of n herein denotes the number of aromatic-alkyne repeat units.The value does not restrict the compound to embodiments wherein eachrepeat unit is identical. In contrast, the compounds of the presentinvention comprise at least one aromatic-alkyne repeat unit which maydiffer from the others by including a moiety at the R₁ position, whichis useful for initializing the cyclization reaction and which may not bepresent on the other repeat units. See Structure (II) below. Accordingto the present invention, each repeat unit may be different. The modularsynthesis of the present invention enables the synthesis of oligo-alkyneand poly-alkyne chains have a wide variety of structural and functionalfeatures.

In the above structure (I), R_(A1), R_(A2), R_(A3), and R_(A4) are eachindependently carbon or nitrogen. In some embodiments, from 1 to 4 ofthe R_(A1), R_(A2), R_(A3), and R_(A4) are carbon. In some embodiments,from 1 to 4 of the R_(A1), R_(A2), R_(A3), and R_(A4) are nitrogen. Themodular assembly of such compounds, as explained more fully herein,enables the preparation of ortho oligo- or poly-alkyne compounds of thepresent invention in which each repeat unit has an identical aromaticring structure. The modular assembly alternatively allows preparation ofcompounds in which each repeat unit has a different aromatic ringstructure. For example, in some embodiments, all of the aromatic ringsin the repeat unit may comprise phenyl groups, which may be substitutedor unsubstituted. In some embodiments, all of the aromatic rings in therepeat unit may comprise pyridyl rings, which may be substituted orunsubstituted. In still other embodiments, one or more of the at leastthree, preferably at least four, aromatic rings may comprise a phenylgroup and one or more of the at least three, preferably at least four,aromatic rings may comprise a pyridyl group. Furthermore, each aromaticring may comprise different substituents. For example, some aromaticrings may be substituted with cyano, while other aromatic rings may besubstituted with alkoxy.

In some embodiments of the above structure (I), R₁, R₂, R₃, and R₄ areeach independently hydrogen; an electron pair (i.e., when thecorresponding ring atom is nitrogen); an aliphatic moiety; an aromaticmoiety; an alkoxy moiety; cyano; nitro; sulfinyl; sulfonyl; amino; or analkylamino. Each repeat unit of structure (I) may comprise differentsubstituents at the R₁, R₂, R₃, and R₄ positions. The aliphatic moiety(e.g., alkyl, alkenyl, alkynyl, cycloalkyl) may have from 1 to 18 carbonatoms, or from 1 to about 14 carbon atoms, or 1 to about 10 carbonatoms, such as 1 to about 6 carbon atoms. The aromatic moiety havingfrom three to 18 carbon atoms, such as from three to 10 carbon atoms, orthree to six carbon atoms. The alkoxy moiety having from 1 to about 6carbon atoms, such as from 1 to about 3 carbon atoms. The alkylamino mayhave from 1 to 18 carbon atoms, or from 1 to about 14 carbon atoms, or 1to about 10 carbon atoms, such as 1 to about 6 carbon atoms. Thealiphatic moiety, aromatic moiety, alkoxy, or alkyl amino moiety may besubstituted or unsubstituted. Substituents include halogen (e.g.,chlorine, bromine, or iodine), amino, xanthate, or cyano.

In some embodiments of the above structure (I), any two of R₁, R₂, R₃,and R₄ of one or more repeat units together with the atoms (carbon,nitrogen, sulfur, or oxygen) to which they are bonded may form a fusedcycloalkyl (which may be homocycloalkyl or heterocycloalkyl) or aromaticring (which may be homoaromatic, such as phenyl, or heteroaromatic) ormultiple fused aromatic rings. Fused heterocycloalkyl and heteroaromaticmoieties may comprise nitrogen (e.g., pyridyl, pyridazinyl, triazinyl),sulfur (e.g., thiophenyl, thiophene, benzothiophene), or oxygen (e.g.,furanyl, tetrahydrofuranyl).

In some preferred embodiments of Structure (I), each of R₁, R₂, R₃, R₄on each repeat unit is hydrogen, other than one repeat unit, whichcomprises a moiety having structure (II) below at the R₁ substituentposition. In some preferred embodiments, at least one of R₁, R₂, R₃, R₄on each repeat unit is cyano. Again, one repeat unit comprises a moietyhaving structure (II) below at the R₁ substituent position. In somepreferred embodiments, both R₂ and R₃ together from a tetrahydrofuran.

The above structure (I) comprises a chain of aromatic-alkyne repeatunits comprising at least three alkyne moieties, such as at least fouralkyne moieties, each of which is bonded to an aromatic ring. At leastone of the aromatic rings among the three or more comprises a moietyhaving the structure (II) below at the R₁ moiety position:

In the above structure (II), Y comprises a reactive moiety, such asbromine, iodine, xanthyl, or a carbonyl compound which can be convertedinto a radical. The xanthyl is generally bonded through the sulfur atom.Xanthates include xanthic acid and esters of xanthic acid, such as alkylesters having from 1 to about 6 carbon atoms, including methyl xanthate,ethyl xanthate, propyl xanthates. This compound may be prepared as shownin Scheme 1 (see FIG. 3) by employing ethynyltrimethylsilane as the

group and deprotecting the compound via base-mediated (for example,potassium carbonate or tetrabutylammonium fluoride) protodesilylation inmethanol/tetrahydrofuran.

In the above structure (II), Z comprises a group selected from among O,S, S(O), SO₂, CR₇R₈, or NR₉. R₇, R₈, and R₉ may be hydrogen, analiphatic moiety (e.g., alkyl, alkenyl, alkynyl, cycloalkyl) having from1 to about 10 carbon atoms, such as 1 to about 6 carbon atoms; anaromatic moiety having from three to 10 carbon atoms (e.g., toluene,naphthyl, para-methoxyphenyl), or six carbon atoms (e.g., phenyl,para-fluorophenyl), or 14 to 20 carbon atoms (anthracene, phenanthrene,alkylanthracene, alkylphenanthrene).

In some preferred embodiments, Z comprises an oxygen atom. In somepreferred embodiments, Z comprises an oxygen atom and Y comprisesbromine. In some preferred embodiments, Z comprises an oxygen atom and Ycomprises iodine. In some preferred embodiments, Z comprises an oxygenatom and Y comprises a xanthate.

Preferably, the repeat unit comprising the above R₁ group substituenthaving structure (II) is located centrally in the ortho oligo- orpoly-alkyne chain such that the compound is essentially symmetrical,i.e., having substantially an equal number (i.e., within 1) of alkynemoieties on either side of the aromatic ring of the repeat unit havingthe above R₁ group substituent. More specifically, if the oligo- orpoly-alkyne chain comprises an even number of repeat units, the R₁ groupsubstituent having structure (II) is located on the aromatic ring of arepeat unit at the n/2 position or the n/2+1 position. For example, ifthe oligo-alkyne of structure (I) comprises six repeat units, the R₁group substituent having structure (II) is located on the aromatic ringof the third or fourth repeat unit. If the oligo-alkyne of structure (I)comprises an odd number of repeat units, the R₁ group substituent havingstructure (II) is located on the aromatic ring at the n/2+0.5 position.For example, if the oligo-alkyne of structure (I) has five repeat units,the R₁ group substituent having structure (II) is located on thearomatic ring of the third repeat unit. This embodiment is preferredsince the cyclization reactions can proceed essentially symmetricallyfrom the central aromatic ring.

The ortho oligo- or poly-alkyne chain of structure (I) may be terminated(represented by groups T₁ and T₂) with a group selected from amonghydrogen, an aliphatic moiety (e.g., alkyl, alkenyl, alkynyl,cycloalkyl, such as tetrahydrofuranyl) having from about 1 to about 18carbon atoms, from 1 to about 14 carbon atoms, or 1 to about 10 carbonatoms, such as 1 to about 6 carbon atoms; an aromatic moiety having fromthree to 18 carbon atoms, such as from three to 10 carbon atoms (e.g.,toluene, naphthyl, para-methoxyphenyl, thiophenyl, furanyl), or sixcarbon atoms (e.g., phenyl, para-fluorophenyl), or 14 to 20 carbon atoms(anthracene, phenanthrene, alkylanthracene, alkylphenanthrene); analkoxy moiety having from 1 to about 6 carbon atoms; or a cyano moiety.

In some embodiments, each of R_(A1), R_(A2), R_(A3), and R_(A4) arecarbon, and the ortho oligo- or poly-alkyne compound for use in themethod of the present invention has the following Structure (III)comprising the general aromatic-alkyne repeat unit:

In the above structure (III), n, R₁, R₂, R₃, R₄, T₁, and T₂ have thesame definitions as provided in connection with structure (I).

In structure (III), at least one of the aromatic rings among the threeor more comprises an R₁ moiety having the structure (II):

wherein Y and Z have been previously defined.

In some preferred embodiments of Structure (III), each of R₁, R₂, R₃, R₄of each repeat unit are hydrogen, other than the repeat unit comprisinga moiety having structure (II) at the R₁ substituent position. In somepreferred embodiments, at least one of R₁, R₂, R₃, R₄ on each repeatunit is cyano. Again, one repeat unit comprises a moiety havingstructure (II) below at the R₁ substituent position. In some preferredembodiments, both R₂ and R₃ together from a tetrahydrofuran.

In order for the cascade to proceed fully without any unreacted alkyneunits remaining after the reaction, initiation proceeds at the centralalkyne. See FIG. 2. Because intermolecular activation does not proceedwith the sufficient selectivity for the substrates with more than threealkynes, the method of the present invention employs intramolecularactivation via introduction of a “weak link,” a chemically differentfunctionality which can be activated selectively in the presence ofmultiple alkynes.

In order to prepare ortho-poly-alkyne chains that can be zipped up toprepare highly cyclized materials, an ortho-alkyne starting material isprepared comprising a moiety representing a “weak link.” Within thecontext of the present invention, “weak link” is terminology for afunctional group which will eventually be employed to initiate radicalcyclization.

Oligo- and poly-alkynes of general structure (I) and of the specificstructures shown in structure (IV) may be prepared by modular synthesisusing a wide variety of aryl-alkyne building blocks. Modular synthesisenables the preparation of oligo-alkynes and poly-alkynes having fouralkyne moieties as shown in Structure (IV) or more, such as five, six,seven, eight, nine, or ten alkynes, or even more such as 11, 12, 13alkynes and so on. According to some embodiments of the presentinvention, a bis-alkyne model compound having a moiety representing the“weak link” and particularly suitable for preparing oligo-alkyne chainshaving an even number of alkyne moieties may have the following generalstructure (IV):

In the context of Structure (IV), R₂, R₃, and R₄ have the samedefinitions as provided in connection with Structure (I). Further, Y andZ have the same definitions as provided in connection with Structure(II).

In the above structure (IV), R₅ and R₆ may be selected from amonghydrogen, an aliphatic moiety (e.g., alkyl, alkenyl, alkynyl,cycloalkyl) having from about 1 to about 18 carbon atoms, from 1 toabout 14 carbon atoms, or 1 to about 10 carbon atoms, such as 1 to about6 carbon atoms; an aromatic moiety having from three to 18 carbon atoms,such as from three to 10 carbon atoms (e.g., toluene, naphthyl,para-methoxyphenyl), or six carbon atoms (e.g., phenyl,para-fluorophenyl), or 14 to 20 carbon atoms (anthracene, phenanthrene,alkylanthracene, alkylphenanthrene); an alkoxy moiety having from 1 toabout 6 carbon atoms; or a cyano moiety.

Examples of model compounds having structure (IV) are provided below:

Scheme 1 (as depicted in FIG. 3) is a sequence of reactions forpreparing bis-alkyne model compounds having a moiety representing the“weak link” starting from 3-iodophenol. The bis-alkyne model compoundshown in FIG. 3 having a moiety representing the “weak link” is combinedwith additional aromatic building blocks to thereby prepare anortho-poly-alkyne compound having multiple ortho-alkyne moieties, suchas at least three ortho-alkyne moieties, preferably at least four alkynemoieties that may be zipped up according to the present invention tothereby prepare graphene ribbons.

According to some embodiments of the present invention, a bis-alkynemodel compound having a moiety representing the “weak link” andparticularly suitable for preparing oligo-alkyne chains having an oddnumber of alkyne moieties may have the following general structures (Va)and (Vb):

In the context of Structures (Va) and (Vb), R₂, R₃, and R₄ have the samedefinitions as provided in connection with Structure (I). Further, Y andZ have the same definitions as provided in connection with Structure(II).

In the above structure, X comprises a leaving group, such as bromine,iodine, or triflate.

In some embodiments, the aromatic building blocks that may be reactedwith the bis-alkyne model compounds having structures (IV) or (V) havinga moiety representing the “weak link” may be represented more generallyby the following structure (VI):

In the context of Structure (VI), R₂ and R₃ have the same definitions asprovided in connection with Structure (I). In some embodiments of theabove structure (VI), each X independently comprises a leaving group,such as bromine, iodine, or triflate. In some embodiments of structure(VI), each X may independently be an alkyne or a leaving group, such asbromine, iodine, or triflate. In still other embodiments of structure(VI), one X may be hydrogen while the other X may be an alkyne or aleaving group, such as bromine, iodine, or triflate.

Specific examples of building blocks having structure (VI) are shownbelow as structures (VIa) through (VIe):

In some embodiments, larger building blocks, e.g., ortho- andpoly-alkynes having six, seven, eight, nine, ten or more repeat unitswhen combined e.g., with a model compound having either of structures(IV) or (V), may be built analogously, e.g., by employing buildingblocks having the following structure (VII):

In the context of Structure (VII), R₂ and R₃ have the same definitionsas provided in connection with Structure (I). In the above structure(VII), X comprises a leaving group, such as bromine, iodine, ortriflate. X may also be an alkyne. In the above structure (VII), Arcomprises an aromatic group, such as an additional leaving groupsubstituted phenyl group or a toluene. Specific Ar groups includephenyl, para-methylphenyl, para-fluorophenyl, para-methoxyphenyl, andTMS.

Specific examples of building blocks having structure (VII) are shown asbelow structures (VIIa) through (VIIe):

The above building blocks depicted in structures (IV) through (VII) (andexemplified in specific structures) may be used in the modular assemblyof oligo-alkyne and poly-alkynes of the invention. See FIG. 4, which isa sequence of reactions depicting the modular assembly of bis-alkynemodel compounds of the type prepared according to the sequence depictedin FIG. 3 with additional aromatic building blocks to thereby prepare anortho-poly-alkyne compound having multiple ortho-alkyne moieties. In theembodiment depicted in FIG. 4, the oligo-alkyne compound comprises fouralkyne moieties. A general structure of an oligo-alkyne compoundcomprising four alkyne moieties is shown in the following structure(VIII):

In the context of Structure (VIII), R₁, R₂, R₃, R₄, T₁, and T₂ have thesame definitions as provided in connection with Structure (I). Further,Y and Z have the same definitions as provided in connection withStructure (II).

In some embodiments of Structure (VIII), the T₁ and T₂ moieties maycomprise aromatic groups, which may be substituted or unsubstituted.Exemplary aromatic groups include phenyl, toluene, thiophenyl, furanyl,imidazole, and pyridyl, among others. In some embodiments, the T₁ and T₂moieties may comprise substituted phenyl groups having the structures:

In the above terminating structures, R₅ and R₆ may be selected fromamong hydrogen, an aliphatic moiety (e.g., alkyl, alkenyl, alkynyl,cycloalkyl) having from about 1 to about 18 carbon atoms, from 1 toabout 14 carbon atoms, or 1 to about 10 carbon atoms, such as 1 to about6 carbon atoms; an aromatic moiety having from three to 18 carbon atoms,such as from three to 10 carbon atoms (e.g., toluene, naphthyl,para-methoxyphenyl), or six carbon atoms (e.g., phenyl,para-fluorophenyl), or 14 to 20 carbon atoms (anthracene, phenanthrene,alkylanthracene, alkylphenanthrene); an alkoxy moiety having from 1 toabout 6 carbon atoms; or a cyano moiety.

Specific examples of oligo-alkynes within the scope of general structure(VIII) are shown below as structures (VIIIa) through (VIIId):

In each of structure (VIIIa), structure (VIIIb), structure (VIIIc), andstructure (VIIId), the alkyl moiety may comprise from 1 to 18 carbonatoms, such as from 1 to 12 carbon atoms, from 1 to 6 carbon atoms, orfrom 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, tert-butyl, and so on.

The model compounds, e.g., the bis-alkyne model compound havingstructure (IV) based on the starting moiety representing the “weak link”and modularly built with additional aromatic building blocks, e.g.,having structure (VII), shown above may be depicted in the below orthopoly-alkyne chain structure (IX) having at least six alkynes:

In the context of Structures (IX), R₂ and R₃ have the same definitionsas provided in connection with Structure (I). Further, Y and Z have thesame definitions as provided in connection with Structure (II). In theabove structure, Ar comprises an aromatic group, such as an additionalleaving group substituted phenyl group or a toluene.

Larger structures may be built in the same modular fashion, having,e.g., a chain of eight alkyne moieties, a chain of 10 alkyne moieties, achain twelve alkyne moieties, or still larger, such as 14, 16, 18, 20,22, or 24 alkyne moieties. In some embodiments, the structures maycomprise oligo-alkynes having odd numbers of alkynes, such as threealkyne moieties, five alkyne moieties, seven alkyne moieties, ninealkyne moieties, or still larger, such as 11, 13, 15, 17, 19, 21 or 23alkyne moieties. These modularly built ortho-poly-alkyne structurescomprising a central “weak link” moiety may be subjected to radicalcyclizations to thereby prepare highly cyclized compounds. In preferredembodiments, the cyclization is carried out using Sonogashira coupling.The Sonogashira reaction is a palladium catalysed carbon-carbon bondforming reaction between an aryl halide (e.g. Br, I) and a terminalalkyne moiety (e.g. HCCR). A general procedure involves a suspension ofaryl halide, PdCl₂(PPh₃)₂, Cu(I) iodide in a amine solvent(triethylamine or diisopropylamine). The solvent is degassed to removethe majority of oxygen possibly in the solution which can catalyze a nondesirable Hay homocoupling side reaction. Once the solution is degassed,alkyne is added and the reaction is initiated.

Initial cyclization efforts using the bis-alkyne model compounds havinga moiety representing the “weak link” using silane-mediated processes(Et₃SiH and TTMSS) led to the products of the desired cascadetransformation. However, the reactions were sluggish and the yields werelow (21-250). A dramatic increase in efficiency was observed when theBu₃SnH/AIBN system was used for the chemoselective cascade initiation.The chemoselective radical attack at the alkyl halide in the presence oftwo alkynes is remarkable considering that alkynes are also reactiveunder these conditions. See Scheme 2, which is depicted in FIG. 5.Scheme 2 depicts cascade cyclization of substituted enediynes andPotential Energy Surface (PES) for the transformation of enediyne 2b(B3LYP/6-31+ (d,p), kcal/mol).

In view of these results, a one-pot cyclization of the tetra-alkyne 11was developed as shown in Scheme 3 (FIG. 6). The transformationproceeded as expected and formed the fully “zipped” cascade product.Although the yield was low for X═Br (26%), the bromide can bequantitatively exchanged to form the iodo tetraalkyne 12 which istransformed in the fully closed nanoribbon 13 in a much higher yield(52% overall, ˜93% per step).

Once selective activation of the “weak link” in the presence of fouralkynes is accomplished, a cascade of four sequential exo-dig alkynecyclizations occurs. Only after all four alkynes are consumed by theradical cascade does the vinyl radical attack the terminal aryl ring.This attack transiently disrupts aromaticity in this ring and is onlyobserved when three or more alkynes are present in the startingmaterial. For these longer oligomers, this transient loss of aromaticityis partially compensated by the aromatization in one of the previouslyformed rings (i.e., ring 3, Scheme 4 (depicted in FIG. 7)). The 1,5H-shift is also favorable because it is assisted by rearomatization. Thefinal H-abstraction step has low stereoselectivity because of nearplanarity of the sterically unencumbered radical center.

The noticeable increase in the efficiency of the iodo-substitutedtetrayne ring closure (Br: 26%, I: 52%) suggests that the initiationstep plays a key role in the success of the overall cascade. Selectivitymay be further improved as the number of alkynes increase or when newfunctional groups are introduced via the optimization of the “weaklink.” In aspect, a promising alternative to the choice of the “weaklink” is provided by xanthates. In view thereof, the bromide or iodidemoiety in the weak link structure may be replaced with a xanthatestructure, as shown in Scheme 3 (FIG. 6), prior to cycliziation.Xanthates can be selectively activated in the presence of alkyne usingeither light or lauroyl peroxide/thermal initiation. Photochemicalactivation is particularly appealing because it is chemically orthogonalto the radical processes discussed above and has the potential to bemore selective.

The synthesis of longer and wider ribbons leads towards the synthesis ofnanoribbon pieces with a number of materials applications. Assembly ofsymmetric alkynes is particularly fast and is further facilitated usinga library of the most common building blocks. A “linchpin” with twoalkynes provides poly-alkynes with an even number of alkyne moieties.See FIG. 8. Starting with a monoalkyne “linchpin” (or any other coremolecule with an odd number of alkynes) provides symmetric moleculeswith an odd number of alkyne moieties. See FIG. 9. However, alloligo-alkynes, independent on having an odd or an even number of thetriple bonds, can be fully converted to a polyaromatic molecules as longas the initiating step occurs at the central alkyne.

In some embodiments, the alternative for increasing molecular dimensionsin the 2D space is to make the ribbons wider. Wider ribbons areavailable when naphthalenes or anthracenes are used instead ofpreexisting benzene rings in the reactants. See FIGS. 10 and 11. In someembodiments, wider ribbons are possible by cyclizing oligo-alkyneshaving the general structure (X):

R₁, R₄, R_(A1), R_(A4), T₁, T₂, and n are as defined in connection withthe definitions of each provided in Structure (I).

R_(F1), R_(F2), R_(F3), R_(F4) are each independently carbon ornitrogen. In some embodiments, R_(F1), R_(F2), R_(F3), R_(F4) comprisesfrom 1 to four carbon atoms. In some embodiments, R_(F1), R_(F2),R_(F3), R_(F4) comprises from 1 to four nitrogen atoms. Accordingly, thearomatic moiety within structure (IX) may be any of naphthalene,quinolone, isoquinoline, quinoxaline, benzo[d][1,2,3]triazine,benzo[e][1,2,4]triazine, 1,5-naphthyridine, 1,6-naphthyridine,1,7-naphthyridine, 1,8-naphthyridine, phthalazine,pyrido[2,3-d]pyridazine, pyrido[3,4-d]pyridazine, among others. Themodular assembly of such compounds enables the preparation of orthooligo- or poly-alkyne compounds of the present invention in which eachrepeat unit has an identical aromatic ring structure. The modularassembly alternatively allows preparation of compounds in which eachrepeat unit has a different aromatic ring structure. For example, insome embodiments, all of the aromatic rings in the repeat unit maycomprise naphthalene groups, which may be substituted or unsubstituted.In some embodiments, all of the aromatic rings in the repeat unit maycomprise, e.g., quinolone or phthalazine rings, which may be substitutedor unsubstituted. In still other embodiments, combinations of thesegroups are possible. Furthermore, each aromatic ring may comprisedifferent substituents. For example, some aromatic rings may besubstituted with cyano, while other aromatic rings may be substitutedwith alkoxy.

In some embodiments of the above structure (X), R_(F11), R_(F22),R_(F33), R_(F44) are each independently hydrogen; an election pair(i.e., when the corresponding ring atom is nitrogen); an aliphaticmoiety; an aromatic moiety; an alkoxy moiety; cyano; nitro; sulfinyl;sulfonyl; amino; or an alkylamino. Each repeat unit of structure (I) maycomprise different substituents at the R₁, R₂, R₃, and R₄ positions. Thealiphatic moiety (e.g., alkyl, alkenyl, alkynyl, cycloalkyl) may havefrom 1 to 18 carbon atoms, or from 1 to about 14 carbon atoms, or 1 toabout 10 carbon atoms, such as 1 to about 6 carbon atoms. The aromaticmoiety having from three to 18 carbon atoms, such as from three to 10carbon atoms, or three to six carbon atoms. The alkoxy moiety havingfrom 1 to about 6 carbon atoms, such as from 1 to about 3 carbon atoms.The alkylamino may have from 1 to 18 carbon atoms, or from 1 to about 14carbon atoms, or 1 to about 10 carbon atoms, such as 1 to about 6 carbonatoms. The aliphatic moiety, aromatic moiety, alkoxy, or alkyl aminomoiety may be substituted or unsubstituted. Substituents include halogen(e.g., chlorine, bromine, or iodine), amino, xanthyl, or cyano.

In some embodiments of the above structure (X), the R_(F11), R_(F22),R_(F33), R_(F44) together with the atoms to which they are bonded mayform a fused cycloalkyl (which may be homocycloalkyl orheterocycloalkyl) or aromatic ring (which may be homoaromatic, such asphenyl, or heteroaromatic) or multiple fused aromatic rings. Fusedheterocycloalkyl and heteroaromatic moieties may comprise nitrogen(e.g., pyridyl, pyridazinyl, triazinyl), sulfur (e.g., thiophenyl,thiophene, benzothiophene), or oxygen (e.g., furanyl,tetrahydrofuranyl).

An exemplary embodiment which may be used to prepare wide ribbons isshown in the following structure (Xa):

R₁, R₂, R₃, R₄, T₁, T₂, Y, and Z are as defined above in connection withstructures (I) and (II).

The modular approach to the construction of poly-alkynes should allowsignificant flexibility. Use of naphthalenes allows preparation ofeither anthracene/naphthalene fusions (naphthalenes on one side of theribbon=one extra layer hexagons) or anthracene/anthracene fusions(naphthalenes on both sides of the ribbon=two extra layers ofpentagons). The prepared ortho-poly-alkyne chains may be cyclized anddehydrogenated (vide infra) in order to use these processes to providefused tetracenes and pentacenes. In principle, fused pentacenes can bealso prepared from antracene containing oligoynes (not shown). Pentaceneitself is an organic semiconductor and valuable electronic material.

Because a variety of acetylenic building blocks can be introduced in thepoly-alkyne precursor via the robust Pd-catalyzed cross-couplingapproach and because the efficiency of exo-dig cyclizations is notaffected strongly by the nature of the aromatic substituents, thechemistry lends itself for introducing and fine-tuning a variety ofelectronic effects in graphene nanoribbons and graphene substructures.Functionalization on the outside of the graphene core will change itselectronic properties and will open up new opportunities for theincorporation of these functionalities into supramolecular assemblies.An additional possibility for introducing substituents is to replaceterminal aryl group by the needed functionality.

Cyclizations of bis-alkynes (enediynes) show that both the cyano and thealkoxy groups are fully compatible with the radical cascade conditions.See FIGS. 12A through 12E (Scheme 5). FIG. 12A depicts the finaloligo-cyclization for preparing a highly cyclized structure with bothcyano and alkoxy (methoxy) functionality. The synthesis of the componentparts of the compound are provided in FIGS. 12B through 12D. TheSongashira coupling reactions are provided in FIG. 12E, including theconditions for cyclization of the assembled compound.

In some embodiments, the present invention is directed to thecyclization of heteroaromatic assemblies. For example, the presentinvention is directed to the synthesis of heteroaromtic assemblies,followed by cyclization to thereby prepare highly cyclized conjugatedpolyheteroaromatic nanostructures. Building block assemblies, accordingto these embodiments of the present invention, may be based onheteroaromatic compounds including pyridine, pyrazine, pyrimidine,pyridazine, triazines, and tetrazines.

In some embodiments, the oligo-alkyne of the present invention maycomprise repeat units having the following general structures (XI) or(XII):

In the above structures, R₁, R₂, R₃, R₄, T₁, T₂, and n are as defined inconnection with Structure (I). Modular assembly enables the preparationof oligo-alkynes combining the repeat units of both Structures (XI) and(XII). Still further, the oligo-alkynes may be prepared using the repeatunits shown in Structures (III), (X), (XI), and (XII).

In another embodiment, the oligo-alkyne of the present invention mayhave the following general structure (XIII):

In the above structures, R₁, R₄, T₁, T₂, and n are as defined inconnection with Structure (I). Modular assembly enables the preparationof oligo-alkynes combining any of the repeat units of Structures (XI),(XII), and (XIII). Still further, the oligo-alkynes may be preparedusing the repeat units shown in Structures (III), (X), (XI), (XII), and(XIII).

Because nitrogen-containing heterocycles are compatible with thesecascades, we can prepare a variety of new polycyclic ligands fordifferent metals with multiple potential applications in molecularelectronics. The examples shown in FIG. 13 illustrate the flexibility ofthis molecular design and the variety of molecular architecturesavailable via structural modifications in the initial oligo-alkyne. Forexample, the top example imposes a planar square geometry on the metalbinding site whereas the bottom designs offer more flexibility and canbe used to fine tune exchange coupling of various 3d transition metalions, in particular the classic Fe^(2+/3+) and Ru^(2+/3+) mixed-valencesystems. The synthetic schemes for preparing each of Compound A, B, andC are provided in FIGS. 14, 15, and 16, respectively.

In any of the oligo-alkyne structures according to the presentinvention, modular assembly allows the linkage of any two or morearomatic-alkyne groups having different structures from each other. Thepresent invention advantageously utilizes cascade transformations toprepare graphene nanoribbons and graphene substructures of nearly anydesign. Current organic synthesis has a lot to offer this new field ofgraphene chemistry by providing access to differentially-substitutedgraphene pieces that could have a number of electronic applications. Theaccomplishment of the design and synthesis of nano-sized electronicscould revolutionize current nano-electronics as there is always theconstant push in the computer industry to make electronics smaller andmore efficient.

The following non-limiting examples are provided to further illustratethe present invention.

EXAMPLES Example 1 Synthesis of Model Enediynes

The following reaction sequence illustrates the general technique forsynthesizing the model compound and for the addition of aromatic-alkynebuilding blocks to the model compound.

Example 2 Optimization of Cascade Initiation

The following reaction sequences were performed in order to optimize theinitiation of the cyclization reaction.

Example 3 Mechanism of Cascade Initiation

The following reaction sequence demonstrates the mechanism of cascadeinitiation of the cyclization reaction.

Example 4 General Procedure for Synthesis Compounds According to thePresent Invention

THF and hexanes used for reactions were dried over sodium and distilled.Hexanes used for column chromatography were distilled prior to use. Allother solvents were used as purchased. Column Chromatography wasperformed using silica gel (60 Å). Unless otherwise noted, all ¹H NMRswere run on 400 MHz and 600 MHz spectrometer in CDCl₃ and CD₃CN and all¹³C NMR were run on 100 MHz and 150 MHz spectrometer in CDCl₃ and CD₃CN.Proton chemical shifts are given relative to the residual proton signalsof the deuterated solvent CDCl₃ (7.26 ppm), CD₃CN (1.94 ppm). Carbonchemical shifts were internally referenced to the deuterated solventsignals in CDCl₃ (77.00 ppm), CD₃CN (1.4, 118.7). All J-coupling valuesare reported in Hertz (Hz).

Example 5 General Procedure for Protection of 2,3 iodophenol with “WeakLink” Group (a)

A suspension of 2,3 iodophenol (0.77 mmol), K₂CO₃ (1.69 mmol) and18-crown-6 (0.04 mmol) in 18 mL of acetone was brought to reflux.Through top of condenser 1,2 dibromoethane (3.06 mmol) was added dropwise. Reaction was monitored by TLC. At completion of reaction, usualaqueous workup was performed. The reaction mixture was purified by flashchromatography on silica gel, (eluent: hexane/EtOAc) on silica gel toafford compound a.

Example 6 Procedure for Synthesis of 3-iodophenyl diethylcarbamate (b)

To a stirred suspension of NaH (1.09 g, 45.47 mmol), in THF (23 mL), asolution of 3-iodophenol (5.00 g, 22.73 mmol), in THF (5.70 mL) was dropwise added at room temperature. After stirring the reaction mixture for2 h. N,N-diethylcarbamoyl chloride (6.17 g, 45.47 mmol) in THF (8 mL)was added. Stirring was continued for another 8 h. Usual aqueous work upgave the crude carbamate which was purified by column chromatography(eluent: hexane/EtOAc) on silica gel to afford compound b.

Example 7 Procedure for Synthesis of 2,3-diiodophenyl diethylcarbamate(c)

n-BuLi (14.95 mL of a 1.6M sol. in hexane, 23.91 mmol) was added tosolution of i-Pr2NH (3.38 mL, 23.91 mmol) in THF (50 mL) at 0° C. After30 min at 0° C. the LDA solution was cooled to −78° C. and the c (21.74mmol) was added. The resulting solution was stirred for 30 min at −78°C. and then iodine (6.62 g, 26.09 mmol) in THF (15 mL) was added. After30 min at low temperature the reaction mixture was allowed to warm toroom temperature, H₂O was added and THF evaporated under reducedpressure. The aqueous phase was extracted with EtOAc (3×25 mL) and thecombined organic layers were washed with 1M HCl, dried over anhydrousNa₂SO₄, and evaporated under reduced pressure. The crude mixture waspurified by column chromatography (eluent: hexane/EtOAc) on silica gelto afford compound c.

Example 8 Procedure for Synthesis of 2,3-diiodophenol (d)

To a solution of the carbamate 3 (10.07 mmol) in EtOH (130 mL) a largeexcess of NaOH (4.03 g, 0.10 mol) was added. The mixture was refluxedfor 5-8 h. After cooling to room temperature most of the EtOH wasevaporated under reduced pressure, the residue was diluted with diethylether and the excess of NaOH was neutralized at 0° C. using a 1Msolution of HCL. The aqueous solution was extracted with diethyl ether(3×20 mL) and the combined organic phase was washed with brine, driedwith Na₂SO₄, and evaporated under reduced pressure. The crude waspurified by column chromatography (eluent: hexane/EtOAc) on silica gelto afford compound d.

Example 9 General Procedure for Sonogashira Cross Coupling of 6 withDifferent Substituted Acetylenes (1)

A suspension of aryl dihalide (0.59 mmol), PdCl₂ (PPh₃)₂ (29.70 μmol),Cu(I) iodide (29.70 μmol) in 15 mL of triethylamine was degassed threetimes with freeze/pump/thaw technique in a flame dried round bottomflask. 2.5 equiv. of 4-ethynyl-anisole (1.49 mmol) was added using asyringe once solution thawed and allowed to react for 8 hours. Thereaction was monitored by TLC. After total consumption of the arylhalide, the reaction mixture was filtered through celite and washed withmethylene chloride (3×30 mL). The organic layer was washed with asaturated solution of ammonium chloride (2×30 mL), water (2×30 mL) anddried over anhydrous Na₂SO₄. Solvent was removed in vacuo. The reactionmixture was purified by flash chromatography on silica gel, (eluent:hexane/EtOAc) on silica gel to afford compound 1.

Example 10 General Procedure for Radical Cascade of (2)

To three separate round-bottom flasks were added 40.00 mg ofbis-methylbenzene (1) in 6 mL of benzene, 59.70 mg Bu₃SnH in 2 mL ofbenzene, and 1.53 mg AIBN in 2 mL benzene. Nitrogen was bubbled inflasks for 20 min to degas solution. Bu₃SnH and AIBN were added bysyringe pump through the top of a condenser over the course of 6 hoursto a refluxing solution of bis-methylbenzene. The reaction was monitoredby TLC. After conversion of all starting material, the reaction mixturewas concentrated and purified by preparatory TLC, (eluent: hexane/EtOAc)on silica gel to afford compound 2.

Example 11 General Procedure for Finkelstein Reaction of (3) and (13)

Sodium iodide was added in one portion in to a stirred solution of (1c)(55 mg, 0.13 mmol) in 10 mL of acetone. The mixture was heated to 50° C.under nitrogen atmosphere for 8 h. Upon completion then solvent wasremoved under vacuum. The resulting solid was dissolved in CH₂Cl₂ andwashed with saturated Na₂S₂O₃, water, brine and dried over anhydrousNa₂SO₄. Solvent was removed in vacuo giving compound (3) in quantitativeyield as a light yellow oil.

Example 12 Procedure for Anionic Cascade Reaction (4) and (5)

A 0.1 M solution of (3) (61 mg, 0.17 mmol) in 15 mL 3:2 hexane/Et₂O wasdeoxygenated by bubbling N₂ for 5 minutes. The mixture was cooled to−78° C. A solution of n-BuLi (0.16 mL of a 1.6 M sol. in hexane, 0.25mmol) was added drop wise. The solution was stirred for 10 more minutesat −78° C. and then the cooling bath was removed. The reaction mixturewas stirred 2.5 h at room temp in order for the cyclization to occur.The cyclized solution was cooled back down to −78° C. and an excess ofMeOH (30.5 μL, 0.77 mmol) was added. After the addition the cooling bathwas removed and the reaction was stirred for 3 h. To the reactionmixture was added deionized water. The mixture was extracted with CH₂Cl₂and washed with ammonium chloride and brine solution 2 times and driedover Na₂SO₄. Solvent was removed in vacuo and purified by flashchromatography on silica gel, (eluent: hexane/EtOAc) on silica gel toafford compounds (4) and (5).

Example 13 Procedure for Deprotection of TMS Protecting Groups (2f)

To a solution of((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis(trimethylsilane)6e (225 mg, 0.57 mmol), in 1:1 mixture of MeOH/THF (18 mL) was addedK₂CO₃ (30 mg, 0.21 mmol). The solution was stirred at room temperaturefor 8 h under nitrogen. Water was added to quench the reaction and usualaqueous work up was performed. The reaction mixture was purified byflash chromatography on silica gel, (eluent: hexane/EtOAc) on silica gelto afford compound 2f.

Example 14 1-(2-bromoethoxy)-2,3-diiodobenzene (a)

Chromatographic purification (10% ethyl acetate in hexanes) affordedcompound a (77%) as a white solid. R_(f)=0.6 (20% ethyl acetate inhexanes); ¹H NMR (400 MHz, CDCl₃): δ 7.52 (dd, J=1.1, 7.9 Hz, 1H), 7.02(t, J=8.0 Hz, 1H), 6.70 (dd, J=3.0, 0.8 Hz, 1H), 4.28 (t, J=6.3 Hz, 2H),3.67 (t, J=6.3 Hz, 2H); ¹³C NMR (150 MHz, CDCl₃): δ 158.1, 132.6, 130.5,111.2, 110.0, 101.5, 69.7, 28.3; HRMS (EI): calcd for C₈H₇OBrI₂ [M]+451.7770. found 451.7760.

Example 15((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))dibenzene (1a)

Chromatographic purification (10% ethyl acetate in hexanes) affordedcompound 1a (720) as a light yellow oil. R_(f)=0.5 (10% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.64 (d, J=6.5 Hz, 2H), 7.61 (dd,J=5.7, 2.3 Hz, 2H), 7.37 (m, 6H), 7.24 (s, 1H), 7.23 (d, J=2.0 Hz, 1H),6.86 (t, J=4.6 Hz, 1H), 4.38 (t, J=6.2, 2H), 3.71 (t, J=6.3, 2H); ¹³CNMR (150 MHz, CDCl₃): δ 158.6, 131.6, 131.6, 131.5, 128.8, 128.4, 128.3,128.3, 127.4, 125.0, 123.6, 123.1, 116.2, 112.9, 98.3, 93.8, 88.1, 84.4,69.0, 28.9; HRMS (EI): calcd for C₂₄H₁₇OBr [M]+ 400.04628. found400.04552.

Example 164,4′-((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis(methylbenzene)(1b)

Chromatographic purification (10% ethyl acetate in hexanes) affordedcompound 1b (83%) as a light yellow oil. R_(f)=0.5 (10% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.49 (dd, J=12.8, 8.0 Hz, 4H), 7.22(d, J=3.8 Hz, 1H), 7.21 (s, 1H), 7.16 (dt, J=7.93, 0.7 Hz, 4H), 6.86(dd, J=6.5, 2.8 Hz, 1H), 4.39 (t, J=6.4 Hz, 2H), 3.72 (t, J=6.4 Hz, 2H),2.38 (s, 6H); ¹³C NMR (150 MHz, CDCl₃): δ 158.6, 138.6, 138.4, 131.6,131.5, 129.1, 129.1, 128.6, 127.6, 125.1, 120.6, 120.2, 116.5, 113.0,98.5, 94.0, 87.6, 83.8, 69.1, 28.8, 21.5; HRMS (EI): calcd for C₂₆H₂₁OBr[M]+ 428.07758. found 428.07769.

Example 174,4′-((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis(fluorobenzene)(1c)

Chromatographic purification (15% ethyl acetate in hexanes) affordedcompound 1c (87%) as a light red oil. R_(f)=0.4 (10% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.55 (m, 4H), 7.24 (t, J=8.0 Hz,1H), 7.20 (dd, J=7.7, 1.1 Hz, 1H), 7.05 (td, J=8.7, 1.6 Hz, 4H), 6.87(dd, J=8.1, 1.1 Hz, 1H), 4.39 (t, J=6.3 Hz, 2H), 3.72 (t, J=6.3 Hz, 2H);¹³C NMR (150 MHz, CDCl₃): δ 163.4 (d, J=13.1 Hz), 161.8 (d, J=13.1 Hz),158.6, 133.54, 133.48, 133.47, 133.41, 128.9, 127.2, 125.0, 119.7 (d,J=3.5 Hz), 119.3 (d, J=3.3 Hz), 116.0, 112.9, 97.1, 92.7, 87.7, 84.1,68.9, 28.8; HRMS (EI): calcd for C₂₄H₁₅OBrF₂ [M]+ 436.02744. found436.02660.

Example 184,4′-((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis(methoxybenzene)(1d)

Chromatographic purification (10% ethyl acetate in hexanes) affordedcompound 1d (74%) as a red oil. R_(f)=0.5 (10% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.53 (dd, J=14.3, 8.9 Hz, 4H), 7.20(d, J=2.9 Hz, 1H), 7.19 (s, 1H), 6.88 (d, J=8.5 Hz, 4H), 6.84 (dd,J=6.1, 3.2 Hz, 1H), 4.38 (t, J=6.4 Hz, 2H), 3.83 (s, 6H), 3.71 (t, J=6.4Hz, 2H); ¹³C NMR (150 MHz, CDCl₃): δ 159.8, 159.7, 158.4, 133.13,133.06, 128.4, 127.5, 125.0, 116.5, 115.8, 115.4, 114.0, 113.98, 112.8,98.3, 93.8, 87.0, 83.2, 69.1, 55.3, 28.9; HRMS (EI): calcd forC₂₆H₂₁O₃Br [M]+ 460.06741. found 460.06803.

Example 19((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis(trimethylsilane)(1e)

Chromatographic purification (10% ethyl acetate in hexanes) affordedcompound 1e (83%) as a tan oil. R_(f)=0.5 (15% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.16 (t, J=8.0 Hz, 1H), 7.11 (dd,J=7.7, 1.0 Hz, 1H), 6.8 (dd, J=8.2, 0.9 Hz, 1H), 4.31 (t, J=6.5 Hz, 2H),3.64 (t, J=6.4 Hz, 2H), 0.28 (s, 9H), 0.27 (s, 9H); ¹³C NMR (150 MHz,CDCl₃): δ 159.2, 128.9, 127.5, 125.7, 116.5, 113.7, 103.8, 102.9, 98.8,69.2, 28.6, 0.05, 0.02; HRMS (EI): calcd for C₁₈H₂₅OBrSi₂ [M]+392.06274. found 392.06123.

Example 20 1-(2-bromoethoxy)-2,3-diethynylbenzene (1f)

Chromatographic purification (5% ethyl acetate in hexanes) affordedcompound 1f (94%) as a brown solid. R_(f)=0.6 (10% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.23 (t, J=8.0 Hz, 1H), 7.15 (d,J=7.7 Hz, 1H), 6.87 (d, J=8.3 Hz, 1H), 4.33 (t, J=6.6 Hz, 2H), 3.56 (s,1H), 3.34 (s, 1H); ¹³C NMR (150 MHz, CDCl₃): δ 159.4, 129.5, 127.1,125.9, 115.5, 113.5, 86.0, 81.7, 81.6, 77.8, 69.1, 28.5; HRMS (EI):calcd for C₁₂H₉OBr [M]+ 247.9837. found 247.9838.

Example 211,1′-((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))dinaphthalene(1g)

Chromatographic purification (10% ethyl acetate in hexanes) affordedcompound 1g (88%) as a light brown oil. R_(f)=0.4 (156 ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 8.68 (dd, J=8.4, 0.7 Hz, 1H), 8.59(dd, J=8.4, 0.7 Hz, 1H), 7.86 (m, 5H), 7.79 (dd, J=7.1, 1.1 Hz, 1H),7.47 (m, 2H), 7.44 (m, 1H), 7.40 (m, 2H), 7.33 (t, J=16.0 Hz, 1H), 7.23(m, 2H), 6.94 (d, J=8.2 Hz, 1H), 4.47 (t, J=6.2 Hz, 2H), 3.80 (t, J=6.3Hz, 2H); ¹³C NMR (150 MHz, CDCl₃): δ 158.9, 133.4, 133.3, 133.14,133.11, 130.9, 130.8, 128.9, 128.8, 128.1, 128.0, 127.4, 127.0, 126.8,126.7, 126.6, 126.4, 126.3, 125.4, 125.18, 125.17, 121.2, 120.8, 116.1,112.4, 96.6, 93.0, 92.0, 89.4, 69.0, 28.8; HRMS (EI): calcd forC₃₂H₂₁OBr [M]+ 500.07758. found 500.07750.

Example 224,4′-((3-(2-iodoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis(fluorobenzene)(3)

Washes with Na₂S₂O₃, water, brine afforded the compound 3 (>99%) as alight yellow oil. R_(f)=0.5; ¹H NMR (600 MHz, CDCl₃): δ 7.57 (m, 2H),7.53 (m, 2H), 7.23 (t, J=8.0 Hz, 1H), 7.19 (dd, J=2.9, 1.1 Hz, 1H), 7.05(t, J=8.6 Hz, 4H), 6.85 (dd, J=3.0, 0.9 Hz, 1H), 4.34 (t, J=13.6 Hz,2H), 3.50 (t, J=13.6 Hz, 2H); ¹³C NMR (150 MHz, CDCl₃): δ 163.4 (d,J=13.2 Hz), 161.8 (d, J=13.2 Hz), 158.4, 133.5 (d, J=6.8 Hz), 133.4 (d,J=6.7 Hz), 128.9, 127.2, 124.9, 119.7 (d, J=3.2 Hz), 119.2 (d, J=3.3Hz), 115.9, 115.7 (d, J=22.2 Hz), 115.6 (d, J=22.0 Hz), 112.7, 97.1,92.7, 87.7, 84.1, 69.6, 0.8; HRMS (EI): calcd for C₂₄H₁₅F₂OI [M]+484.0136. found 484.0133.

Example 232,2′-((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis((p-tolylethynyl)benzene)(11a)

Chromatographic purification (20% ethyl acetate in hexanes) affordedcompound 11a (84%) as an oil. R_(f)=0.2 (15% ethyl acetate in hexanes);¹H NMR (600 MHz, CD₃CN): δ 7.56 (d, J=0.8 Hz, 1H), 7.54 (d, J=1.4 Hz,1H), 7.46 (m, 2H), 7.36 (dd, J=8.0, 4.7 Hz, 2H), 7.33 (td, J=15.3, 9.5Hz, 2H), 7.30 (m, 1H), 7.29 (m, 2H), 7.28 (m, 1H), 7.25 (m, 1H), 7.21(td, J=15.3, 7.6 Hz, 1H), 7.12 (d, J=7.9 Hz, 2H), 7.05 (d, J=7.9 Hz,2H), 7.02 (dd, J=8.4, 0.9 Hz, 1H), 4.32 (t, J=5.9 Hz, 2H), 3.53 (t,J=5.9 Hz, 2H), 2.29 (s, 3H), 2.25 (s, 3H); ¹³C NMR (150 MHz, CD₃CN): δ160.2, 140.2, 140.0, 133.4, 133.2, 132.8, 132.6, 132.5, 132.4, 130.9,130.3, 130.2, 129.7, 129.6, 129.2, 129.16, 128.0, 126.6, 126.57, 126.3,126.1, 126.05, 120.8, 120.76, 116.2, 114.7, 97.8, 94.8, 94.7, 93.5,92.8, 89.3, 88.5, 88.4, 70.2, 30.6, 21.64, 21.6; HRMS (EI): calcd forC₄₂H₂₉BrO [M]+ 628.14018. found 628.14014.

Example 242,2′-((3-(2-iodoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis((p-tolylethynyl)benzene)(12a)

Chromatographic purification (15% ethyl acetate in hexanes) affordedcompound 12a (99%) as a oil. R_(f)=0.3 (15% ethyl acetate in hexanes);¹H NMR (600 MHz, CDCl₃): δ 7.63 (d, J=7.5 Hz, 1H), 7.55 (d, J=7.6 Hz,1H), 7.52 (d, J=7.6 Hz, 1H), 7.50 (d, J=7.7 Hz, 1H), 7.43 (d, J=7.9 Hz,2H), 7.40 (d, J=7.9 Hz, 2H), 7.28 (t, J=7.3 Hz, 2H), 7.24 (m, 3H), 7.19(t, J=7.5 Hz, 1H), 7.12 (d, J=7.9 Hz, 2H), 7.08 (d, J=7.9 Hz, 2H), 6.89(d, J=8.2 Hz, 1H), 4.22 (t, J=7.5 Hz, 2H), 3.18 (t, J=7.5 Hz, 2H), 2.35(s, 3H), 2.33 (s, 3H); ¹³C NMR (150 MHz, CDCl₃): δ 158.7, 138.4, 132.5,132.3, 131.7, 131.6, 131.5, 129.0, 128.95, 128.9, 128.0, 127.9, 127.6,126.1, 126.0, 125.6, 125.59, 125.5, 120.2, 116.3, 113.5, 97.2, 93.9,93.7, 92.9, 92.0, 88.2, 87.8, 87.7, 70.2, 21.5, 21.49, 0.6; HRMS (EI):calcd for C₄₂H₂₉IO [M]+ 676.12631. found 676.12625.

Example 252,2′-((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis((phenylethynyl)benzene)(11b)

Chromatographic purification (20% ethyl acetate in hexanes) affordedcompound 11b (84%) as a orange oil. R_(f)=0.2 (15% ethyl acetate inhexanes); ¹H NMR (700 MHz, CDCl₃): δ 7.62 (d, J=7.6 Hz, 1H), 7.54 (m,4H), 7.50 (m, 3H), 7.31 (m, 3H), 7.29 (m, 2H), 7.25 (m, 6H), 7.19 (t,J=7.6 Hz, 1H), 6.91 (d, J=8.2 Hz, 1H), 4.28 (t, J=6.8 Hz, 2H), 3.41 (t,J=6.9 Hz, 2H); ¹³C NMR (100 MHz, CDCl₃): δ 158.9, 132.5, 132.3, 131.8,131.75, 131.64, 131.6, 129.0, 128.3, 128.2, 128.1, 128.0, 127.9, 127.8,127.75, 126.1, 125.7, 125.6, 125.4, 123.23, 123.2, 113.7, 97.1, 93.6,93.4, 92.8, 92.0, 88.4, 88.3, 88.2, 69.3, 28.4; HRMS (EI): calcd forC₄₀H₂₅OBr [M]+ 600.1089. found 600.1088.

Example 262,2′-((3-(2-iodoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis((phenylethynyl)benzene)(12b)

Chromatographic purification (20% ethyl acetate in hexanes) affordedcompound 12b (99%) as a orange oil. R_(f)=0.2 (15% ethyl acetate inhexanes); ¹H NMR (400 MHz, CDCl₃): δ 7.62 (d, J=7.4 Hz, 1H), 7.53 (m,5H), 7.50 (m, 2H), 7.27 (m, 11H), 7.19 (t, J=6.7 Hz, 1H), 6.89 (d, J=8.1Hz, 1H), 4.23 (t, J=7.4 Hz, 2H), 3.20 (t, J=7.4 Hz, 2H); ¹³C NMR (100MHz, CDCl₃): δ 158.6, 132.5, 132.3, 131.8, 131.64, 131.6, 129.0, 128.3,128.2, 128.1, 128.0, 127.9, 127.8, 126.1, 125.7, 125.6, 125.5, 125.4,123.2, 116.2, 113.4, 97.0, 93.6, 93.4, 92.8, 92.0, 90.8, 88.4, 88.3,70.1, 0.6; HRMS (EI): calcd for C₄₀H₂₅IO [M]+ 648.53037. found 648.5357.

Example 272,2′-((3-(2-bromoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis(((4-methoxyphenyl)ethynyl)benzene)(11c)

Chromatographic purification (25% ethyl acetate in hexanes) affordedcompound 11c (82%) as an orange-red oil. R_(f)=0.1 (156 ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.64 (d, J=7.5 Hz, 1H), 7.56 (d,J=7.7 Hz, 1H), 7.53 (d, J=7.7 Hz, 1H), 7.49 (d, J=8.5 Hz, 3H), 7.46 (d,J=8.6 Hz, 2H), 7.31 (d, J=7.7 Hz, 1H), 7.25 (m, 4H), 7.18 (t, J=7.6 Hz,1H), 6.91 (d, J=8.2 Hz, 1H), 6.83 (d, J=8.6 Hz, 2H), 6.79 (d, J=8.6 Hz,2H), 4.29 (t, J=6.8 Hz, 2H), 3.78 (s, 3H), 3.76 (s, 3H), 3.44 (t, J=6.8Hz, 2H); ¹³C NMR (150 MHz, CDCl₃): δ 159.6, 159.5, 158.8, 133.3, 133.2,133.1, 132.5, 132.2, 131.5, 131.3, 128.9, 128.0, 127.9, 127.7, 127.4,126.0, 125.8, 125.6, 125.5, 125.3, 116.3, 115.3, 113.9, 113.8, 113.76,113.7, 97.2, 93.8, 93.5, 92.9, 91.9, 88.0, 87.2, 87.1, 69.3, 55.15,55.1, 28.5; HRMS (ESI): calcd for C₄₂H₂₉BrO₃ [M]+ 683.11978. found683.12098.

Example 292,2′-((3-(2-iodoethoxy)-1,2-phenylene)bis(ethyne-2,1-diyl))bis(((4-methoxyphenyl)ethynyl)benzene)(12c)

Chromatographic purification (25% ethyl acetate in hexanes) affordedcompound 12c (99%) as an orange-red oil. R_(f)=0.1 (156 ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.63 (d, J=7.6 Hz, 1H), 7.55 (d,J=7.7 Hz, 1H), 7.51 (d, J=7.7 Hz, 1H), 7.48 (m, 3H), 7.45 (d, J=8.8 Hz,2H), 7.29 (t, J=7.6 Hz, 1H), 7.24 (m, 4H), 7.18 (t, J=3.2 Hz, 1H), 6.89(d, J=8.2 Hz, 1H), 6.83 (d, J=8.7 Hz, 2H), 6.80 (d, J=8.6 Hz, 2H), 4.24(t, J=7.4 Hz, 2H), 3.79 (s, 3H), 3.78 (s, 3H), 3.22 (t, J=7.4 Hz, 2H);¹³C NMR (150 MHz, CDCl₃): δ 159.6, 159.55, 158.6, 133.2, 133.1, 132.5,132.3, 131.5, 131.4, 128.9, 128.0, 127.9, 127.8, 127.4, 126.1, 125.8,125.7, 125.5, 125.4, 116.2, 115.4, 115.36, 113.9, 113.83, 113.8, 113.5,97.2, 93.8, 93.5, 92.9, 91.9, 88.1, 87.2, 87.1, 70.2, 55.2, 0.6; HRMS(ESI): calcd for C₄₂H₂₉IO₃ [M]+ 709.12396. found 709.12371.

Example 30(E)-5-benzylidene-4-phenyl-3,5-dihydro-2H-cyclopenta[de]chromene (2a)

Chromatographic purification (15% ethyl acetate in hexanes) affordedcompound 2a (63%) as a yellow oil. R_(f)=0.3 (15% ethyl acetate inhexanes); ¹H NMR (700 MHz, CDCl₃): δ 7.54 (d, J=3.9 Hz, 2H), 7.46 (m,5H), 7.40 (m, 1H), 7.36 (tt, J=9.9, 1.5 Hz, 1H), 7.28 (s, 1H), 7.02 (m,1H), 7.00 (d, J=7.5 Hz, 1H), 6.88 (t, J=7.8 Hz, 1H), 6.72 (d, J=8.0 Hz,1H), 4.24 (t, J=5.7 Hz, 2H), 2.92 (t, J=5.7 Hz, 2H); ¹³C NMR (150 MHz,CDCl₃): δ 151.0, 141.7, 137.0, 134.8, 134.1, 134.0, 133.0, 131.6, 130.4,130.2, 129.9, 129.4, 128.4, 128.3, 128.2, 126.9, 116.6, 114.6, 67.1,25.3; UV/Vis (MeOH): λ_(max)=273 nm; HRMS (EI): calcd for C₂₄H₁₈O [M]+322.1358. found 322.1349.

Example 31(E)-5-(4-methylbenzylidene)-4-(p-tolyl)-3,5-dihydro-2H-cyclopenta[de]chromene(2b)

Chromatographic purification (15% ethyl acetate in hexanes) affordedcompound 2b (70%) as a yellow oil. R_(f)=0.3 (15% ethyl acetate inhexanes); ¹H NMR (600 MHz, CD₃CN): δ 7.46 (d, J=7.6 Hz, 2H), 7.34 (d,J=7.6 Hz, 2H), 7.30 (d, J=7.6 Hz, 2H), 7.27 (d, J=7.6 Hz, 2H), 7.24 (s,1H), 7.08 (d, J=7.6 Hz, 1H), 6.90 (t, J=7.7 Hz, 1H), 6.72 (d, J=8.0 Hz,1H), 4.26 (t, J=5.6 Hz, 2H), 2.93 (t, J=5.7 Hz, 2H), 2.40 (s, 6H); ¹³CNMR (150 MHz, CD₃CN): δ 152.5, 142.4, 140.0, 138.2, 135.7, 135.4, 135.3,134.2, 133.0, 132.7, 131.4, 130.8, 130.49, 130.47, 128.1, 117.6, 115.6,68.4, 26.3, 21.8, 21.7; UV/Vis (MeOH): λ_(max)=274 nm; HRMS (EI): calcdfor C₂₆H₂₂O [M]+ 350.16707. found 350.16618.

Example 32(E)-5-(4-fluorobenzylidene)-4-(4-fluorophenyl)-3,5-dihydro-2H-cyclopenta[de]chromene(2c)

Chromatographic purification (15% ethyl acetate in hexanes) affordedcompound 2c (87%) as a red oil. R_(f)=0.4 (15% ethyl acetate inhexanes); ¹H NMR (600 MHz, CD₃CN): δ 7.55 (dd, J=8.5, 5.6 Hz, 2H), 7.43(dd, J=8.5, 5.7 Hz, 2H), 7.20 (q, J=8.9 Hz, 3H), 7.17 (d, J=4.8 Hz, 1H),6.99 (d, J=7.5 Hz, 1H), 6.90 (t, J=7.8 Hz, 1H), 6.73 (d, J=8.1 Hz, 1H),4.24 (t, J=5.8 Hz, 2H), 2.89 (t, J=5.8 Hz, 2H); ¹³C NMR (150 MHz,CD₃CN): δ 164.1 (d, J=107.5 Hz), 162.5 (d, J=105.6 Hz), 152.3, 142.7,134.9, 134.1 (d, J=3.27 Hz), 133.9, 133.4, 132.9 (d, J=72.6 Hz), 132.7(d, J=72.6 Hz), 132.6, 131.8 (d, J=3.3 Hz), 130.8, 128.2, 117.23, 116.5,116.4 (d, J=4.2 Hz), 116.2, 115.7, 68.0, 25.8; UV/Vis (MeOH): λmax=301nm; HRMS (EI): calcd for C₂₄H₁₆OF₂ [M]+ 358.11693. found 358.11632.

Example 33(E)-5-(4-methoxybenzylidene)-4-(4-methoxyphenyl)-3,5-dihydro-2H-cyclopenta[de]chromene(2d)

Chromatographic purification (15% ethyl acetate in hexanes) affordedcompound 2d (74%) as a red oil. R_(f)=0.4 (20% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.53 (d, J=8.0 Hz, 2H), 7.34 (d,J=4.1 Hz, 2H), 7.25 (t, J=5.3 Hz, 1H), 7.19 (s, 1H), 7.00 (d, 4.1 Hz,2H), 6.96 (d, 4.1 Hz, 2H), 6.92 (t, 5.7 Hz, 1H), 6.76 (d, 8.0 Hz, 1H),4.30 (t, 5.6 Hz, 2H), 3.88 (s, 3H), 3.87 (s, 3H), 2.96 (t, 5.6 Hz, 2H);¹³C NMR (150 MHz, CDCl₃): δ 159.7, 158.6, 150.8, 140.7, 134.1, 132.9,131.3, 131.1, 130.3, 130.2, 130.1, 126.5, 116.3, 114.2, 113.8, 113.79,113.3, 67.2, 55.3, 25.3; UV/Vis (MeOH): λmax=275 nm; HRMS (EI): calcdfor C₂₆H₂₂O₃ [M]+ 382.15690. found 382.15644.

Example 34(E)-trimethyl((4-(trimethylsilyl)-2H-cyclopenta[de]chromen-5(3H)-ylidene)methyl)silane(2e)

Chromatographic purification (15% ethyl acetate in hexanes) affordedcompound 2e (74%) as a yellow oil. R_(f)=0.4 (20% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.22 (d, J=7.5 Hz, 1H), 7.07 (t,J=7.7 Hz, 1H), 6.73 (d, J=8.0 Hz, 1H), 6.54 (s, 1H), 4.28 (t, J=5.9 Hz,2H), 2.99 (t, J=5.8 Hz, 2H), 0.34 (s, 9H), 0.30 (s, 9H); ¹³C NMR (150MHz, CDCl₃): δ 159.7, 150.9, 146.0, 138.2, 136.7, 131.5, 127.3, 116.5,114.2, 67.2, 27.7, 1.3, 0.2; UV/Vis (MeOH): λ_(max)=224 nm; HRMS (EI):calcd for C₁₈H₂₆OSi₂ [M]+ 314.1522. found 314.1522.

Example 35(E)-4-(naphthalen-1-yl)-5-(naphthalen-1-ylmethylene)-3,5-dihydro-2H-cyclopenta[de]chromene(2f)

Chromatographic purification (15% ethyl acetate in hexanes) affordedcompound 2f (80%) as a yellow oil. R_(f)=0.5 (15% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 8.08 (m, 1H), 7.96 (m, 1H), 7.92(dd, J=6.8, 2.7 Hz, 1H), 7.87 (d, J=7.8 Hz, 2H), 7.79 (d, J=8.6 Hz, 1H),7.77 (d, J=7.0 Hz, 1H), 7.61 (m, 2H), 7.55 (m, 2H), 7.51 (m, 1H), 7.47(m, 1H), 7.39 (m, 1H), 7.33 (s, 1H), 6.83 (t, J=7.8 Hz, 1H), 6.77 (d,J=4.1 Hz, 1H), 6.71 (d, J=7.4 Hz, 1H), 4.33 (t, J=5.8 Hz, 2H), 2.80 (t,J=5.7 Hz, 2H); ¹³C NMR (150 MHz, CDCl₃): δ 150.9, 144.3, 134.4, 134.2,133.8, 133.5, 133.0, 132.5, 132.4, 131.6, 131.5, 130.1, 128.7, 128.65,128.4, 128.36, 128.0, 127.4, 126.9, 126.7, 126.2, 126.1, 126.0, 125.9,125.3, 125.2, 125.1, 120.1, 116.9, 114.9, 67.2, 25.4; UV/Vis (MeOH):λ_(max)=320 nm; HRMS (EI): calcd for C₃₂H₂₂O [M]+ 422.1671. found422.1664.

Example 36 2-(4-fluorophenyl)-4-((4-fluorophenyl)ethynyl)benzofuran (4)

Chromatographic purification (10% ethyl acetate in hexanes) affordedcompound 4 (38%) as a red brown solid. R_(f)=0.8 (10% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.88 (m, 2H), 7.60 (m, 2H), 7.50(d, J=8.2 Hz, 1H), 7.41 (dd, J=2.7, 0.6 Hz, 1H), 7.26 (t, J=5.2 Hz, 1H),7.16 (m, 3H), 7.09 (tt, J=8.7, 1.9 Hz, 2H); ¹³C NMR (150 MHz, CDCl₃): δ163.9, 163.5, 155.7, 154.4, 133.6, 133.5, 131.3, 127.0, 126.97, 126.5,124.1, 116.0 (d, J=22.0 Hz), 115.7 (d, J=22.2 Hz), 115.4, 111.5, 100.7,91.5, 86.8; HRMS (EI): calcd for C₂₂H₁₂OF₂ [M]+ 330.08563. found330.08580.

Example 37 2,3-bis((4-fluorophenyl)ethynyl)phenol (5)

Chromatographic purification (10% ethyl acetate in hexanes) affordedcompound 5 (55%) as a red orange oil. R_(f)=0.2 (10% ethyl acetate inhexanes); ¹H NMR (600 MHz, CDCl₃): δ 7.55 (m, 2H), 7.51 (m, 2H), 7.23(t, J=15.9 Hz, 1H), 7.13 (dd, J=2.9, 0.9 Hz, 1H), 7.08 (m, 2H), 7.04 (m,2H), 6.97 (dd, J=8.3, 1.0 Hz, 1H), 5.91 (bs, 1H); ¹³C NMR (150 MHz,CDCl₃): δ 163.6 (d, J=36.2 Hz), 162.0 (d, J=35.7 Hz), 156.4, 133.6,133.5, 129.8, 125.8, 124.1, 119.2, 118.5, 115.9 (d, J=22.7 Hz), 115.7(d, J=22.0 Hz), 114.8, 112.0, 99.0, 92.3, 87.6, 81.8; HRMS (EI): calcdfor C₂₂H₁₂OF₂ [M]+ 330.08563. found 330.08483.

Example 3913-methyl-11-(p-tolyl)-1,2,11,19c-tetrahydrobenzo[6,7]benzo[1′,2′]fluoreno[3′,4′:4,5]indeno[1,2,3-de]chromene (13a)

Chromatographic purification (20% ethyl acetate in hexanes) affordedcompound 13a as a mixture of diastereomers X═Br (26%) X═I (52%) as adark yellow oil. The oil crystallized upon slow evaporation in a 3:1mixture of methanol:hexane to provide crystals of one of the individualdiastereomers while the other diastereomer remained an oil. Thesediastereomers were separated by filtration. R_(f)=0.2 (15% ethyl acetatein hexanes); ¹H NMR (600 MHz, CDCl₃): δ 9.08 (d, J=8.3 Hz, 1H), 9.02 (d,J=7.7 Hz, 1H), 8.50 (d, J=8.3 Hz, 1H), 7.91 (d, J=8.0 Hz, 1H), 7.86 (d,7.4 Hz, 1H), 7.73 (t, J=7.7 Hz, 1H), 7.52 (m, 2H), 7.44 (m, 2H), 7.34(d, J=7.8 Hz, 2H), 7.23 (s, 1H), 7.15 (d, J=7.9 Hz, 2H), 7.13 (t, J=7.9Hz, 1H), 7.02 (d, J=8.1 Hz, 1H), 6.74 (d, J=8.0 Hz, 1H), 5.28 (s, 1H),4.97 (td, J=12.6, 4.7 Hz, 1H), 4.69 (dd, J=11.7, 6.3 Hz, 1H), 3.53 (dd,J=14.2, 3.5 Hz, 1H), 2.35 (s, 3H), 2.34 (s, 3H), 2.28 (m, 1H), 1.98 (m,1H); ¹³C NMR (150 MHz, CDCl₃): δ 153.7, 150.1, 147.9, 139.3, 138.3,136.6, 136.53, 136.5, 135.8, 131.1, 130.2, 129.94, 129.9, 129.8, 129.7,129.5, 129.48, 128.9, 128.8, 128.7, 128.2, 127.9, 127.7, 127.4, 127.2,127.1, 125.4, 125.1, 124.8, 124.5, 124.3, 123.4, 116.2, 114.8, 65.2,51.9, 38.7, 30.8, 21.4, 21.1; UV/Vis (MeOH): λmax=421 nm; HRMS (EI):calcd for C₄₂H₃₀O [M]+ 550.2297. found 550.2253. The 2^(nd) diastereomerwas also a yellow oil. R_(f)=0.2 (15% ethyl acetate in hexanes); ¹H NMR(600 MHz, CDCl₃): δ 8.98 (d, J=8.2 Hz, 2H), 8.50 (d, J=8.3 Hz, 1H), 7.96(d, J=8.0 Hz, 1H), 7.80 (d, J=7.1 Hz, 1H), 7.72 (t, J=7.4 Hz, 1H), 7.54(d, J=7.6 Hz, 1H), 7.49 (t, J=7.6 Hz, 1H), 7.43 (m, 2H), 7.13 (m, 2H),7.04 (m, 3H), 6.89 (m, 2H), 6.76 (d, J=7.9 Hz, 1H), 5.61 (s, 1H), 5.30(s, 1H), 4.97 (td, J=12.4, 4.4 Hz, 1H), 4.69 (dd, J=11.4, 7.2 Hz, 1H),3.53 (dd, J=14.0, 4.0 Hz, 1H), 2.33 (s, 3H), 2.29 (s, 3H), 1.97 (m, 1H);¹³C NMR (150 MHz, CDCl₃): δ 154.7, 150.1, 145.4, 139.2, 138.3, 138.0,137.0, 136.5, 134.9, 133.6, 132.5, 130.3, 130.1, 129.9, 129.8, 129.4,129.3, 129.2, 129.1, 128.9, 128.7, 128.6, 127.7, 127.1, 125.2, 124.9,124.5, 124.3, 123.3, 123.1, 121.7, 118.4, 115.0, 113.3, 65.2, 51.8,30.8, 29.7, 21.7, 21.6; UV/Vis (MeOH): λ_(max)=498 nm; HRMS (EI): calcdfor C₄₂H₃₀O [M]+ 550.2297. found 550.2290.

Example 4011-phenyl-1,2,11,19c-tetrahydrobenzo[6,7]benzo[1′,2′]fluoreno[3′,4′:4,5]indeno[1,2,3-de]chromene (13b)

Chromatographic purification (20% ethyl acetate in hexanes) affordedcompound 13b as a mixture of diastereomers, 1:1.1, X═Br (35%) X═I (55%)as a orange oil. R_(f)=0.3 (10% ethyl acetate in hexanes); ¹H NMR (700MHz, CDCl₃): δ 9.07 (d, J=7.9 Hz, 1H), 9.02 (t, J=8.9 Hz, 2H), 8.92 (d,J=8.5 Hz, 2H), 8.50 (d, J=7.6 Hz, 2H), 8.47 (d, J=8.2 Hz, 1H), 8.12 (d,J=7.9 Hz, 1H), 8.08 (d, J=7.28 Hz, 2H), 7.84 (d, J=7.8 Hz, 2H), 7.79 (d,J=8.5 Hz, 2H), 7.69 (q, J=7.0 Hz, 2H), 7.56 (d, J=7.6 Hz, 3H), 7.53 (q,J=7.1 Hz, 2H), 7.50 (s, 2H), 7.44 (m, 7H), 7.39 (s, 2H), 7.35 (t, J=7.4Hz, 3H), 7.30 (m, 5H), 7.23 (m, 7H), 7.17 (m, 4H), 7.06 (d, J=7.6 Hz,1H), 7.01 (t, J=8.1 Hz, 2H), 6.76 (t, J=7.7 Hz, 2H), 5.68 (s, 1H), 5.35(s, 1H), 5.06 (t, J=6.1 Hz, 2H), 4.70 (m, 2H), 3.02 (d, J=13.7 Hz, 2H),2.67 (m, 2H), 1.83 (m, 2H); ¹³C NMR (150 MHz, CDCl₃): δ 153.9, 149.6,144.1, 142.2, 140.7, 136.4, 134.2, 132.6, 131.1, 130.1, 129.2, 129.1,128.9, 128.8, 128.6, 128.4, 127.8, 127.2, 127.17, 127.1, 126.8, 126.7,126.6, 126.1, 124.5, 124.3, 124.2, 124.0, 123.7, 123.5, 121.0, 116.0,115.4, 112.9, 111.2, 64.1, 54.9, 54.4, 43.1, 31.4, 29.7; UV/Vis (MeOH):λ_(max)=465 nm; HRMS (EI): calcd for C₄₀H₂₆O [M]+ 522.19837. found522.19865.

Example 4113-methoxy-11-(4-methoxyphenyl)-1,2,11,19c-tetrahydrobenzo[6,7]benzo[1′,2′]fluoreno[3′,4′:4,5]indeno[1,2,3-de]chromene (13c)

Chromatographic purification (20% ethyl acetate in hexanes) affordedcompound 13c as a mixture of diastereomers, 1:1.3, X═Br (32%) X═I (55%)as a yellow-orange oil. R_(f)=0.2 (10% ethyl acetate in hexanes); ¹H NMR(700 MHz, CDCl₃): δ 9.08 (d, J=8.3 Hz, 1H), 9.03 (m, 2H), 8.98 (t, J=7.7Hz, 2H), 8.50 (d, J=8.5 Hz, 2H), 8.18 (m, 1H), 8.03 (d, J=8.6 Hz, 0.5H),7.99 (d, J=8.3 Hz, 1.5 Hz), 7.94 (d, J=8.7 Hz, 1H), 7.84 (m, 2H), 7.78(m, 1H), 7.72 (q, J=3.2 Hz, 2H), 7.66 (m, 1H), 7.63 (d, J=7.7 Hz, 1H),7.54 (t, J=8.5 Hz, 2H), 7.50 (q, J=3.9 Hz, 3H), 7.42 (m, 5H), 7.36 (d,J=8.3 Hz, 3H), 7.17 (m, 1H), 7.13 (q, J=7.8 Hz, 2H), 6.96 (m, 2H), 6.84(m, 1H), 6.76 (m, 8H), 5.58 (s, 1H), 5.26 (s, 1H), 4.97 (m, 2H), 4.76(m, 1H), 4.70 (m, 3H), 4.62 (dd, J=12.0, 4.4 Hz, 1H), 3.80 (s, 3H), 3.79(s, 3H), 3.78 (s, 2H), 3.75 (s, 2H), 3.53 (d, J=11.0 Hz, 2H), 3.04 (d,J=12.5 Hz, 1H), 1.96 (m, 2H); ¹³C NMR (150 MHz, CDCl₃): δ 159.0, 158.9,158.8, 158.7, 158.6, 158.4, 153.6, 153.58, 152.5, 152.0, 151.9, 144.1,142.0, 136.5, 136.4, 135.5, 135.4, 134.8, 134.7, 134.0, 133.4, 133.1,130.9, 129.8, 129.3, 129.2, 129.1, 129.0, 128.9, 128.8, 128.75, 128.7,128.65, 126.6, 128.1, 127.9, 127.4, 127.3, 127.2, 126.9, 125.4, 125.2,124.7, 124.5, 124.3, 124.2, 124.1, 124.07, 124.0, 123.95, 123.9, 116.1,116.0, 114.9, 114.6, 114.59, 114.4, 114.3, 111.9, 111.8, 111.7, 110.9,110.2, 68.2, 65.1, 55.5, 55.4, 55.2, 55.16, 54.1, 53.5, 42.2, 42.1,30.9, 30.8, 29.7, 29.6; UV/Vis (MeOH): λ_(max)=428 nm; HRMS (EI): calcdfor C₄₂H₃₀O₃ [M]+ 582.2195. found 582.2196.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method of preparing a multicyclic structurecomprising: cyclizing a compound comprising repeat units having thefollowing structure (I):

wherein: n is an integer having a value of at least three and less than25; Ra₁, Ra₂, Ra₃, and Ra₄ are each independently carbon or nitrogen;and R₁, R₂, R₃, and R₄ are each independently selected from the groupconsisting of hydrogen, a substituted or unsubstituted aliphatic moiety,and a substituted or unsubstituted alkoxy; wherein the substituents ofsubstituted aliphatic moiety are selected from the group consisting ofchlorine, bromine, amino, and cyano; or, alternatively, R_(A1), R_(A2),R_(A3), and R_(A4) are each carbon; R₁, R₂, R₃, and R₄ are eachindependently selected from the group consisting of hydrogen and asubstituted or unsubstituted aliphatic moiety; wherein the substituentsof substituted aliphatic moiety are selected from the group consistingof chlorine, bromine, amino, and cyano; and any two adjacent R_(A1),R_(A2), R_(A3), and R_(A4) and the R₁, R₂, R₃, and R₄, respectivelybonded thereto together with the atoms to which they are bonded completenaphthalene or anthracene; T₁ and T₂ are each independently selectedfrom the group consisting of hydrogen, an aliphatic moiety having from 1to 18 carbon atoms; an aromatic moiety having from three to 18 carbonatoms; an alkoxy moiety having from 1 to 6 carbon atoms; and a cyanomoiety; and further wherein at least one of the repeat units comprisesan R₁ moiety having the structure (II):

wherein: Y is selected from the group consisting of bromine, iodine,xanthyl, or a carbonyl compound which can be converted into a radical;and Z is selected from the group consisting of O, S, S(O), SO₂, CH₂, orNCH₃.
 2. The method of claim 1 wherein the compound of structure (I) iscyclized by contacting the compound with a palladium-copper(I) ioncatalyst.
 3. The method of claim 1 wherein n has a value between fourand
 25. 4. The method of claim 1 wherein the compound has the followingstructure (III):

wherein n has a value between four and 25; R₁, R₂, R₃, R₄, T₁, and T₂are as defined in claim 1; and further wherein at least one of therepeat units comprises an R₁ moiety having the structure (II):

wherein Y and Z are as defined in claim
 1. 5. The method of claim 1wherein the compound has the following structure (VIII):

wherein R₁, R₂, R₃, R₄, T₁, T₂, Y, and Z are as defined in claim
 1. 6.The method of claim 5 wherein the compound has a structure selected fromthe group consisting of structure (VIIIa), structure (VIIIb), structure(VIIIc), and structure (VIIId):


7. The method of claim 1 wherein the compound has the followingstructure (IX):

wherein R₁, R₂, R₃, R₄, T₁, T₂, Y, and Z are as defined in claim
 1. 8.The method of claim 1 wherein the compound has the following structure(Xa):

wherein R₂, R₃, Y, and Z are as defined above in connection withclaim
 1. 9. The method of claim 1 wherein the compound has a structureselected from the group consisting of structure (XI), structure (XII),and structure (XIII):

wherein n has a value of between four and 25; R₁, R₂, R₃, R₄, T₁, and T₂are as defined in claim 1; and further wherein at least one of therepeat units comprises an R₁ moiety having the structure (II):

wherein Y and Z are as defined in claim
 1. 10. A conjugated,polyaromatic compound prepared by cyclizing the compound havingstructure (I) according to the method of claim 1.